Pi = 3.14159 (and an infinite number of decimal places after that). Pi Day, which is celebrated on 3/14 at 1:59 p.m., is an international holiday that was born at the Exploratorium. Watch some Pi Day celebrations.

Webcasts made possible through the generosity of the Gordon and Betty Moore Foundation, the Jim Clark Endowment for Internet Education, the McBean Family Foundation.

Bandwidth and infrastructure support for connectivity to the California Research and Education Network and to other Internet2-connected networks provided by the Corporation for Educational Networks Initiatives in California (CENIC).